1. Field of the Invention
The present invention relates to a hinge used on a ladder, and particularly to a hinge on an articulated ladder with which a lock mechanism are provided with three lock pins and specific lock holes to perform different lock position respectively.
2. Description of Related Art
It is known that many types of hinges have been developed and used on an articulated metal ladder. For instance, Taiwanese patent published number 282057 discloses a ladder hinge which provides a lock mechanism being operated by way of a trigger pressing slide pins under restoring forces of springs. Furthermore, U.S. Pat. No. 4,566,150 discloses a ladder hinge having a lock mechanism being operated by way of a pair of locking pins transversely passing through two of four apertures on support plats. However, the prior art hinges are sophisticate in structure and inconvenient in operation.
An object of the present invention is to provide a ladder hinge in which three locking pins are located radially and spaced apart to each other to pass through engaging holes specifically distributing on casings of the hinge radially for performing different lock positions respectively.
Another object of the present invention is to provide a ladder hinge, which offers a locking mechanism having fewer parts to simplify the required procedure of assembly.
A further object of the present invention is to provide a ladder hinge, which offers each lock position thereof a sufficient stability and safety.
A further object of the present invention is to provide a ladder hinge with which each lock position can be obtained easily and conveniently.